This invention relates to a storage system having a function of dispersing load that is imposed by access from clients among plural ports.
The recent evolution of IT systems in corporations has given them an unwanted chance of receiving great damage such as data loss or unexpected interruption of business which are caused by computer virus attacks and natural and manmade disasters including typhoons, earthquakes and fires. In order to avoid such damage, each PC user in a corporation has to manage his/her PC properly and thoroughly by taking a backup of data, updating the OS, running a virus check, upgrading software to a newer version, etc. However, being very time-consuming and labor-consuming, PC management is a burden to the users.
Storage-centric networks have been disclosed to address the problem (see, for example, an online news release titled “The concept of a storage-centric network which is ‘safe and secure anywhere’ jointly developed”, retrieved from Hitachi, Ltd.'s homepage on Dec. 8, 2004, <URL http://www.hitachi.com/New/cnews/031120.html>). In a storage-centric network, data stored in local disks of PCs is gathered in a large-capacity storage system connected to the PCs via a network so that the data is backed up and checked for a virus infection in a centralized manner.
Introduction of a storage-centric network enables a system administrator to singularly manage client PCs. As a result, the running cost is greatly reduced. Also, a security patch is applied to every client PC by simply applying the security patch to an OS or an application in a storage system. Worms and viruses are thus prevented from spreading all over the IT system. Furthermore, a storage-centric network makes it possible to prevent leakage of sensitive information through a PC that is stolen or inadvertently left behind by a user who has been carrying the PC around with him/her since such files are not kept in local disks of client PCs.